Add --force-update: immediate signed-update check, stage + service restart

README.md

@@ -149,6 +149,8 @@ OpenSSL; the matching public key lives in `internal/update/pubkey.go`
 (one-time setup: `openssl genpkey -algorithm ed25519 -out private.pem`,
 `openssl pkey -in private.pem -pubout -out public.pem`; private key goes
 to the `RELEASE_SIGNING_KEY` repo secret, public key is committed).
+`gpu-turnstile --force-update` checks immediately, stages the new binary
+and restarts the running service (elevating via UAC only if needed).
 
 ### Docker
 

SPEC.md

@@ -246,6 +246,11 @@ executable location as-is instead.
   idle the process exits with code 3 so the service recovery restarts it
   on the new version. Interactive runs only log "restart to apply".
   `dev` builds and builds without an embedded public key never update.
+- **`--force-update`** runs the same check immediately: it downloads,
+  verifies and stages a newer release, and if the service is running it
+  restarts it right away (otherwise the new version applies on next
+  start). On Windows it elevates via UAC only when the stage or restart
+  needs permissions the caller does not have.
 - **Signing setup (one time)**: `openssl genpkey -algorithm ed25519 -out
   private.pem`; `openssl pkey -in private.pem -pubout -out public.pem`.
   Private key → repo secret `RELEASE_SIGNING_KEY`; public key → committed into

cmd/gpu-turnstile/main.go

@@ -8,6 +8,7 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"io/fs"
 	"log/slog"
 	"net"
 	"net/http"
@@ -45,8 +46,9 @@ func stdoutIsTerminal() bool {
 
 // parseFlags extracts -config <path> (or -config=<path>), the
 // --install-service / --remove-service switches, --no-copy, -h/--help,
-// -v/--version and the hidden --elevated-child marker from args.
+// -v/--version, --force-update and the hidden --elevated-child marker from
-func parseFlags(args []string) (configPath string, install, remove, noCopy, help, showVersion, elevatedChild bool, rest []string) {
+// args.
+func parseFlags(args []string) (configPath string, install, remove, noCopy, help, showVersion, forceUpdate, elevatedChild bool, rest []string) {
 	rest = args[:0]
 	for i := 0; i < len(args); i++ {
 		switch {
@@ -65,13 +67,15 @@ func parseFlags(args []string) (configPath string, install, remove, noCopy, help
 			help = true
 		case args[i] == "-v" || args[i] == "--version" || args[i] == "-version":
 			showVersion = true
+		case args[i] == "--force-update" || args[i] == "-force-update":
+			forceUpdate = true
 		case args[i] == "--elevated-child":
 			elevatedChild = true
 		default:
 			rest = append(rest, args[i])
 		}
 	}
-	return configPath, install, remove, noCopy, help, showVersion, elevatedChild, rest
+	return configPath, install, remove, noCopy, help, showVersion, forceUpdate, elevatedChild, rest
 }
 
 // versionLine is printed at the top of every help and error screen.
@@ -84,6 +88,8 @@ Usage:
   gpu-turnstile --install-service [--no-copy] [-config path]  install + start as a service
   gpu-turnstile --remove-service                              stop + uninstall the service
   gpu-turnstile -v | --version                                print just the version
+  gpu-turnstile --force-update                                check for a signed update now,
+                                                              apply it and restart the service
   gpu-turnstile -h | --help                                   this help
 
 Options:
@@ -114,12 +120,12 @@ func fatalUsage(format string, args ...any) {
 }
 
 func main() {
-	configPath, install, remove, noCopy, help, showVersion, elevatedChild, args := parseFlags(os.Args[1:])
+	configPath, install, remove, noCopy, help, showVersion, forceUpdate, elevatedChild, args := parseFlags(os.Args[1:])
 	if showVersion {
 		fmt.Println(version)
 		return
 	}
-	bare := configPath == "" && !install && !remove && !elevatedChild && len(args) == 0
+	bare := configPath == "" && !install && !remove && !forceUpdate && !elevatedChild && len(args) == 0
 	if help || (bare && stdoutIsTerminal()) {
 		// Bare invocation in a terminal (e.g. double-clicked on Windows)
 		// shows the help instead of starting a proxy window with no visible
@@ -140,10 +146,14 @@ func main() {
 	switch {
 	case install && remove:
 		fatalUsage("error: --install-service and --remove-service are mutually exclusive")
+	case forceUpdate && (install || remove):
+		fatalUsage("error: --force-update cannot be combined with --install-service/--remove-service")
 	case install:
 		os.Exit(serviceCommand(configPath, true, noCopy, elevatedChild))
 	case remove:
 		os.Exit(serviceCommand(configPath, false, noCopy, elevatedChild))
+	case forceUpdate:
+		os.Exit(forceUpdateCommand(configPath, elevatedChild))
 	}
 	if len(args) > 0 {
 		fatalUsage("error: unknown arguments: %s", strings.Join(args, " "))
@@ -245,6 +255,102 @@ func newLogger(cfg config.Config) (*slog.Logger, io.Writer, io.Closer) {
 	return log, out, closer
 }
 
+// waitForEnter keeps an elevated child's console window open until the
+// user has read the output.
+func waitForEnter() {
+	fmt.Print("\nPress Enter to close this window...")
+	bufio.NewReader(os.Stdin).ReadString('\n')
+}
+
+// elevateAndMirror relaunches the current command elevated (UAC) and
+// mirrors the child's exit code. verb is used in messages.
+func elevateAndMirror(verb string) (int, bool) {
+	args := append(append([]string{}, os.Args[1:]...), "--elevated-child")
+	code, err := service.RelaunchElevated(args)
+	if errors.Is(err, service.ErrUserCancelled) {
+		fmt.Fprintln(os.Stderr, "gpu-turnstile: UAC prompt declined")
+		return 1, true
+	}
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "gpu-turnstile: could not elevate: %v\n", err)
+		return 1, true
+	}
+	if code != 0 {
+		fmt.Fprintf(os.Stderr, "gpu-turnstile %s failed in the elevated process (exit %d)\n", verb, code)
+		return code, true
+	}
+	return 0, true
+}
+
+// isPermission reports whether err is a permission problem (Windows
+// ERROR_ACCESS_DENIED, POSIX EACCES/EPERM, possibly wrapped).
+func isPermission(err error) bool {
+	return errors.Is(err, fs.ErrPermission) || strings.Contains(strings.ToLower(err.Error()), "access is denied")
+}
+
+// forceUpdateCommand checks for a signed update immediately, stages it if
+// newer, and restarts the service when it is running so the new binary
+// takes effect. Staging into a system directory and restarting a service
+// need admin rights; instead of prompting unconditionally, permission
+// failures trigger the UAC relaunch so a dev copy in a user-writable
+// directory updates without a prompt.
+func forceUpdateCommand(configPath string, elevatedChild bool) int {
+	if elevatedChild {
+		defer waitForEnter()
+	}
+	cfg, err := loadMergedConfig(configPath)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "%s\n\ngpu-turnstile: %v\n", versionLine(), err)
+		return 1
+	}
+	exePath, err := os.Executable()
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "gpu-turnstile: cannot locate executable: %v\n", err)
+		return 1
+	}
+	log, _, logCloser := newLogger(cfg)
+	defer logCloser.Close()
+	u := &update.Updater{Repo: cfg.UpdateRepo, Asset: cfg.UpdateAsset, Version: version, Log: log}
+
+	ctx, cancel := context.WithTimeout(context.Background(), 2*time.Minute)
+	defer cancel()
+	staged, err := u.Check(ctx, exePath)
+	if err != nil && isPermission(err) && !service.Elevated() {
+		code, _ := elevateAndMirror("--force-update")
+		if code == 0 {
+			fmt.Println("update applied (elevated)")
+		}
+		return code
+	}
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "%s\n\ngpu-turnstile: update check failed: %v\n", versionLine(), err)
+		return 1
+	}
+	if !staged {
+		fmt.Printf("%s is up to date\n", versionLine())
+		return 0
+	}
+	fmt.Printf("%s: update staged\n", versionLine())
+	restarted, err := service.RestartIfRunning()
+	if err != nil && isPermission(err) && !service.Elevated() {
+		code, _ := elevateAndMirror("--force-update")
+		if code == 0 {
+			fmt.Println("update applied (elevated)")
+		}
+		return code
+	}
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "gpu-turnstile: update staged but service restart failed: %v\n", err)
+		return 1
+	}
+	if restarted {
+		fmt.Println("service restarted on the new version")
+	} else {
+		fmt.Println("no running service; the new version applies on next start")
+	}
+	return 0
+}
+
 // serviceCommand installs (copyBin = register the canonical-layout copy)
 // or removes the service and reports the result. On Windows, when the
 // shell is not elevated, the command relaunches itself through a UAC
@@ -252,27 +358,22 @@ func newLogger(cfg config.Config) (*slog.Logger, io.Writer, io.Closer) {
 // waits for a keypress so its console window does not flash closed before
 // the output can be read.
 func serviceCommand(configPath string, install, noCopy, elevatedChild bool) int {
-	verb, done := "remove", "removed"
+	verb, doneVerb := "remove", "removed"
 	if install {
-		verb, done = "install", "installed"
+		verb, doneVerb = "install", "installed"
+	}
+	if elevatedChild {
+		defer waitForEnter()
 	}
 	if !service.Elevated() {
-		args := append(append([]string{}, os.Args[1:]...), "--elevated-child")
+		code, done := elevateAndMirror(verb)
-		code, err := service.RelaunchElevated(args)
+		if done && code != 0 {
-		if errors.Is(err, service.ErrUserCancelled) {
-			fmt.Fprintln(os.Stderr, "gpu-turnstile: UAC prompt declined")
-			return 1
-		}
-		if err != nil {
-			fmt.Fprintf(os.Stderr, "gpu-turnstile: could not elevate: %v\n", err)
-			return 1
-		}
-		if code != 0 {
-			fmt.Fprintf(os.Stderr, "gpu-turnstile service %s failed in the elevated process (exit %d)\n", verb, code)
 			return code
 		}
-		fmt.Printf("service %s: %s (elevated)\n", service.Name, done)
+		if done {
-		return 0
+			fmt.Printf("service %s: %s (elevated)\n", service.Name, doneVerb)
+			return 0
+		}
 	}
 	var err error
 	if install {
@@ -284,17 +385,11 @@ func serviceCommand(configPath string, install, noCopy, elevatedChild bool) int
 	} else {
 		err = service.Remove()
 	}
-	if elevatedChild {
-		defer func() {
-			fmt.Print("\nPress Enter to close this window...")
-			bufio.NewReader(os.Stdin).ReadString('\n')
-		}()
-	}
 	if err != nil {
 		fmt.Fprintf(os.Stderr, "gpu-turnstile service %s: %v\n", verb, err)
 		return 1
 	}
-	fmt.Printf("service %s: %s\n", service.Name, done)
+	fmt.Printf("service %s: %s\n", service.Name, doneVerb)
 	return 0
 }
 

internal/service/service_linux.go

@@ -186,3 +186,16 @@ func Remove() error {
 	}
 	return nil
 }
+
+// RestartIfRunning restarts the systemd unit when it is active (used after
+// a forced update staged a new binary). Reports whether a restart
+// happened. An inactive or missing unit is not an error. Needs root.
+func RestartIfRunning() (bool, error) {
+	if err := exec.Command("systemctl", "is-active", "--quiet", Name+".service").Run(); err != nil {
+		return false, nil // inactive or not installed
+	}
+	if out, err := exec.Command("systemctl", "restart", Name+".service").CombinedOutput(); err != nil {
+		return false, fmt.Errorf("systemctl restart (run as root): %w (%s)", err, out)
+	}
+	return true, nil
+}

internal/service/service_other.go

@@ -40,3 +40,6 @@ func Elevated() bool { return true }
 
 // RelaunchElevated is unsupported on non-Windows, non-Linux platforms.
 func RelaunchElevated([]string) (int, error) { return 0, errUnsupported }
+
+// RestartIfRunning is a no-op on platforms without service integration.
+func RestartIfRunning() (bool, error) { return false, nil }

internal/service/service_windows.go

@@ -351,3 +351,48 @@ func configuredLogFile(configPath string) string {
 	}
 	return values["LOG_FILE"]
 }
+
+// RestartIfRunning restarts the service when it is installed and running
+// (used after a forced update staged a new binary). Reports whether a
+// restart happened. A service that is not installed or not running is not
+// an error. Needs elevation.
+func RestartIfRunning() (bool, error) {
+	m, err := mgr.Connect()
+	if err != nil {
+		return false, fmt.Errorf("connect to service manager (run as administrator): %w", err)
+	}
+	defer m.Disconnect()
+	s, err := m.OpenService(Name)
+	if err != nil {
+		return false, nil // not installed
+	}
+	defer s.Close()
+	st, err := s.Query()
+	if err != nil {
+		return false, fmt.Errorf("query service: %w", err)
+	}
+	if st.State != svc.Running && st.State != svc.StartPending {
+		return false, nil
+	}
+	if _, err := s.Control(svc.Stop); err != nil {
+		return false, fmt.Errorf("stop service: %w", err)
+	}
+	deadline := time.Now().Add(30 * time.Second)
+	for {
+		st, err = s.Query()
+		if err != nil {
+			return false, fmt.Errorf("query service: %w", err)
+		}
+		if st.State == svc.Stopped {
+			break
+		}
+		if time.Now().After(deadline) {
+			return false, fmt.Errorf("service did not stop within 30s")
+		}
+		time.Sleep(300 * time.Millisecond)
+	}
+	if err := s.Start(); err != nil {
+		return false, fmt.Errorf("start service: %w", err)
+	}
+	return true, nil
+}